JP2639058B2 - Tertiary aminoalkyl-hydroxyalkyl ether of polygalactomannan - Google Patents

Description

The present invention relates to the technical field of water-soluble polymers.

[Prior art] Polygalactomannans, especially natural guar gum and locust bean gum (locust beam gum),
It is a substance that has been known for a long time and has been used in many industrial applications. In order to improve the performance of these gums and expand their field of use, polygalactomannans have also been modified by reaction with various compounds to form derivatives of this gum. Examples of such derivatives include hydroxyalkyl ethers of polygalactomannans, aminoalkyl ethers of polygalactomannans, and mixed derivatives of carboxyalkyl-hydroxyalkyl ethers and carboxyalkyl-aminoalkyl ethers of polygalactomannans.

Hydroxyalkyl ether derivatives of polygalactomannans are described in U.S. Pat. No. 3,326,890. The aminoalkyl ether of this gum is disclosed in U.S. Pat.
Issue. Mixed carboxyalkyl-hydroxyalkyl derivatives are described in U.S. Pat. No. 3,723,912. Mixed derivatives containing both anionic groups (eg, carboxyalkyl groups) and cationic groups (eg, aminoalkyl groups) are disclosed in US Pat. No. 3,467,647.

An important use of polygalactomannans and their derivatives is as industrial thickeners. However, in many cases, it is desired to reduce the viscosity of the aqueous fluid after providing the aqueous fluid having the increased viscosity for its intended purpose. This reduction in viscosity is accomplished by using a substance called a "viscosity breaker" or "breaker" that acts on the water-soluble polymer of the thickener to reduce its molecular weight and reduce the viscosity of the fluid in which it is dissolved. Will be

Viscosity destruction (brea) of aqueous gels or thickened aqueous fluids
king) has been performed using a variety of methods. One example of such a method is described in US Pat. No. 4,169,791,
It is a method based on the decomposition action of acids, enzymes or mild oxidizing agents. U.S. Pat. No. 4,464,268 states that sodium hypochlorite is a remarkable treating agent for decomposing water-soluble polymers. The use of ammonium persulfate or alkali metal salts in combination with tertiary amines is described in U.S. Pat. No. 4,250,044 as a suitable viscosity-breaking system for highly viscous fluids. Oil and Gas Journal, December 1983
On page 12, pages 96-101, it is described that lithium hypochlorite is a viscosity-breaking substance. Various methods of thickening aqueous fluids and reducing their viscosity are described in U.S. Pat.
Nos. 0, 3,779,914, 4,144,179 and 4,5
No. 52,668. As described in US Pat. No. 4,654,043, starch sizing agents are degraded upon treatment with hypochlorite and amino compounds.

U.S. Patent No. 4,647,385, assigned to the present applicant,
It is described that the viscosity of the thickened aqueous solution is reduced by adding an alkali metal or alkaline earth metal hypochlorite salt and a tertiary amine to the solution. The combined use of a metal hypochlorite and a tertiary amine results in a much higher rate of viscosity reduction and more complete degradation of the polymer in solution than when the metal salt is used alone.

[Problems to be Solved by the Invention] The thickened high-viscosity aqueous fluid is used in an oil recovery process, especially in a subterranean formation fractuati.
on). In this formation crushing operation, a highly viscous fluid in which insoluble particulate material is suspended
It is injected under water pressure into a well that penetrates the formation. The pressurized fluid creates cracks and fractures in the formation. Suspended insoluble particles are pressed into the fissure and support the fissure open when the crushing pressure is released. Before returning the well to service, the highly viscous fluid must be removed from the well. If the viscosity can be rapidly reduced, this can be easily removed.

The industry continues to seek improved and efficient thickeners and more efficient viscosity-breaking systems for aqueous fluids.

[Means for Solving the Problems] The present invention relates to a novel derivative of polygalactomannan. In one aspect, the invention relates to double derivatives of polygalactomannan. In another aspect, the invention relates to a thickened aqueous fluid obtained using this dual derivative. In yet another aspect, the invention relates to a method for reducing the viscosity of a thickened aqueous fluid.

A novel derivative comprising a tertiary aminoalkyl ether-hydroxyalkyl ether of polygalactomannan, which is suitable for the present invention, is provided. The degree of substitution of this product (D
S), the amount of tertiary aminoalkyl ether substituent, is in the range of about 0.001 to 0.2. The molecular substitution degree (MS) of the product, i.e. the amount of hydroxyalkyl ether substituents, is in the range of about 0.05 to 1.6.

The compositions of the present invention are used to thicken or gel aqueous fluids in various applications. Examples of such applications include drilling of oil and gas wells, fracturing formations where boreholes penetrate as finishing and refurbishment fluids, or industrial, personal, carpet dyeing, waste disposal, etc. Can be If necessary, the viscosity of the thickened or gelled aqueous fluid can be reduced by the addition of alkali metal or alkaline earth metal hypochlorite or chlorinated isocyanurate.

[Action] The water-soluble polymer of the present invention is a tertiary aminoalkyl-hydroxyalkyl ether derivative of polygalactomannan. Such polymers are obtained by reacting polygalactomannans with dialkylaminoalkyl halides or epoxides and alkylene oxides.

The polygalactomannans used for producing the derivative of the present invention are hydrocolloid polysaccharides mainly composed of galactose units and mannose units, and include guar (guar, cluster beans), locust beans (locust beans), and American locust beans (Honey locust), Australian blue-grilled (flam)
e tree) is usually present in the endosperm of legume seeds. For example, guar is based on galactomannan, which is a linear mannan with essentially a single constituent galactose branch. Mannose units are linked by 1,4-β-glycosidic bonds, and galactose branching occurs through 1-6 bonds of every other mannose unit. Therefore, the ratio of galactose units to mannose units contained in the guar polymer is 1: 2.

Locust bean gum is also a polygalactomannan with a similar molecular structure, but the ratio of galactose units to mannose units is 1: 4. Guar and locust bean gum
It is a preferred source of polygalactomannan, mainly because it is readily available commercially.

In the production of the polygalactomannan derivative of the present invention, a tertiary aminoalkylating agent that can be used for tertiary aminoalkyl etherification has 1 to 6 carbon atoms in each alkyl group, and a total of 12 or less carbon atoms. Dialkylaminoalkyl halide or dialkylaminoalkyl epoxide. Halides include chloride, bromide and iodide, with chloride being preferred.

Examples of useful tertiary aminoalkylating agents are dimethylaminomethyl chloride, dimethylaminoethyl chloride, dimethylaminopropyl chloride, methylethylaminopropyl bromide, dimethylaminoisopropyl chloride, methylethylaminoisopropyl chloride, diethylaminobutyl iodide, 3 -Dimethylamino-1,2-
Epoxypropane, 3-diethylamino-1,2-epoxypropane, and other isomers.

The hydroxyalkylating agent which can be used for the hydroxyalkyl etherification in the production of the polygalactomannan derivative of the present invention has an alkylene group having 2 carbon atoms.
-4 is an alkylene oxide wherein the epoxide group is attached to an adjacent carbon atom. Examples of alkylene oxides are ethylene oxide, propylene oxide-1,2, butylene oxide-1,2 and butylene oxide-2,3. The preferred alkylene oxide is propylene oxide-1,2.

The polygalactomannan derivatives of the present invention are prepared by first forming a hydroxyalkyl ether derivative and then reacting with a tertiary aminoalkylating agent to form a tertiary aminoalkyl derivative. Polygalactomannan can be in the form of powder or granules, or split (sp.
lits) and can be reacted with the above two derivative-forming agents. This reaction can be performed in an aqueous system, a non-aqueous system, or a mixed system using an alkali as a condensing agent or a catalyst. When powdery or granular polygalactomannan is used, a preferred reaction medium is a lower alcohol-water mixed solvent, for example, a mixed solvent of methanol or isopropanol and water. The preferred reaction medium for the split is water.

The amount of the alkali catalyst used in the above reaction is about 0.1 to 5% by weight based on the weight of the polygalactomannan. When a halide or a hydrohalide is used as the tertiary aminoalkylating agent, the amount of the alkali catalyst used is at least equivalent to the halogen present in the tertiary aminoalkylating agent, preferably in excess. Amount.

The reaction of polygalactomannans with alkylene oxides is described in detail in U.S. Patent Nos. 3,326,890 and 3,723,409. The reaction of polygalactomannan with a dialkylaminoalkyl halide or epoxide is:
It is described in U.S. Pat. No. 3,498,912.

The compound of the present invention contains about 1 unit of galactomannan.
Degree of substitution of hydroxyalkyl ether group of 0.05 to 1.6 mol, more preferably about 0.3 to 1.0 mol (degree of molecular substitution, MS)
It is preferable to have The preferred degree of substitution (DS) for the tertiary aminoalkyl ether groups is from about 0.001 to 0.2 mole per galactomannan unit, more preferably from about 0.004 to 0.1 mole.
Will be in the mole range.

The viscosity of the aqueous solution thickened by the compound of the present invention can be reduced by adding an alkali metal or alkaline earth metal hypochlorite or a chlorinated isocyanurate to the aqueous solution. Examples of hypochlorite include magnesium hypochlorite, calcium hypochlorite, lithium hypochlorite, sodium hypochlorite, and potassium hypochlorite. Particularly preferred metal salts are the sodium and calcium salts of hypochlorous acid.

Examples of the chlorinated isocyanurate that can be used in the present invention include trichloro-s-triazinetrione, sodium dichloro-s-triazinetrione, potassium dichloro-s-triazinetrione, and sodium dichloro-s-triazinetrione dihydrate. And mixtures thereof.

When performing thickening and viscosity reduction of aqueous fluids according to the present invention, about 10 to 80 pounds (4.53 to 36.3 kg) of tertiary aminoalkyl-hydroxyalkyl ether polygalactomannan per 1000 gallons (3785) of aqueous fluid is used. Thickens aqueous fluids. The amount of the tertiary aminoalkyl-hydroxyalkyl ether polygalactomannan can be
Preferably within the range of about 20 to 60 pounds per gallon.

The amount of metal hypochlorite or chlorinated isocyanurate used to reduce the viscosity of the thickened aqueous fluid can be from about 0.1 to 5 pounds per 1000 gallons of aqueous fluid (0.045 to 2.27 kPa).
g), preferably about 0.5 to 2 pounds (0.227 to 0.907 kg).

The pH of the thickened aqueous fluid before the addition of hypochlorite or chlorinated isocyanurate is about 6-11, preferably about 7-10. The temperature of the breaker system of the present invention is about 50
Will be in the range of ~ 300 ° F (10-149 ° C). The breaker system of the present invention is particularly useful at temperatures between about 70-250 ° F (21-121 ° C).

Hereinafter, the present invention will be described in detail with reference to examples. Parts and percentages are by weight unless otherwise indicated.

Example 1 A suitable reactor was charged with 69.3 parts of powdered hydroxypropyl guar having an MS of 0.4 and 125 parts of isopropyl alcohol. Stirring was started and a nitrogen sparge was applied. 18 ℃
At a temperature of dimethylaminopropyl chloride hydrochloride 11.9
A solution of parts dissolved in 35 parts of deionized water was added over 20 minutes. Ten minutes later, the addition of a solution prepared by dissolving 8 parts of sodium hydroxide in 35 parts of water was started, and when the addition was completed in 20 minutes,
During that time the temperature rose to 23 ° C. Heating was started and the temperature was raised to 70 ° C. in 35 minutes. The temperature was maintained at 70 ° C. for 1 hour and then lowered to 21 ° C. The contents of the reactor were
It was mixed with 500 parts by volume of a 60/40 mixture of water. After immersion and standing for 30 minutes, the liquid phase was separated and discarded. Another 500 parts by volume of methanol / water (60/40) were added and after soaking for 30 minutes, the liquid phase was separated and removed. The swollen gum product was mixed with 1000 parts of acetone and soaked for 30 minutes. The mixture was filtered under reduced pressure using a Buchner funnel and washed with 300 parts of acetone.
The gum product was spread on trays and air dried overnight. 71 parts of air-dried product were recovered.

A solution of this guar product in deionized water is
The solution was prepared at a concentration of 40 pounds (18.1 kg) (40 lb / 1000 gal) of guar derivative per 1000 gallons (3785). pH
After hydration at 6.0 for 2 hours, the pH was adjusted to 8.0 with a dilute aqueous sodium hydroxide solution. The viscosity of this solution was 127 Fan units as measured by a fan viscometer. 0.9 ml of a 3% aqueous solution of calcium hypochlorite was added. The viscosity dropped to 22 fan units after one minute.

Example 2 A suitable reactor was charged with 90 parts of powdered hydroxypropyl guar gum (MS 0.4) and 175 parts of isopropyl alcohol. Nitrogen sparge and stirring were started. After 15 minutes at a temperature of 21 ° C., a solution of 0.1 part of methyl ether of hydroquinone, 0.1 part of citric acid and 25 parts of deionized water was added over 5 minutes. After 10 minutes, a solution of 7.9 parts of dimethylaminopropyl chloride hydrochloride in 25 parts of water was added over 15 minutes. After 10 minutes, a solution of 6 parts of sodium hydroxide in 40 parts of water was added over 12 minutes. The temperature was then raised to 75 ° C over 33 minutes and held at 75 ° C for 2 hours 30 minutes. The temperature was then reduced to 22C. The contents of the reactor were washed three times with 1000 parts by volume of a 60/40 mixture of methanol / water. After each wash, the liquid phase was decanted. The gum product was then mixed with 500 parts by volume of methanol.
The liquid phase was separated from the gum product by vacuum filtration on a Buchner funnel. The contents on the funnel were washed again with 500 parts by volume of acetone under reduced pressure. The product was spread on a tray and dried at room temperature over the weekend. 82.2 parts of the guar derivative product were recovered.

Example 3 A suitable reactor was charged with 90 parts of powdered guar gum and 200 parts of isopropyl alcohol. Stirring and nitrogen sparge were started. After 1 hour and 5 minutes, 6 parts of sodium hydroxide and 50 parts of water
The dissolved aqueous solution was added over 20 minutes. Temperature 24 ℃
, The addition of 29 parts of propylene oxide was started, and the addition was completed in 5 minutes. 60 ° C for 20 minutes
And kept at 60 ° C. for 2 hours and 5 minutes.

Next, a solution of 7.9 parts of dimethylaminopropyl chloride hydrochloride dissolved in 25 parts of water was added over 30 minutes. The temperature was raised to 70 ° C. in 15 minutes and held at 70 ° C. for 2 hours. The temperature was then reduced to room temperature. After washing, dehydrating and drying in the same manner as in Example 2, 91.4 parts of the product were recovered.

Example 4 A suitable reactor was charged with 1760 parts of deionized water, 170 parts of a 50% aqueous sodium hydroxide solution, and 4 parts of borax. The temperature was raised to 170 ° F (77 ° C) and 2,000 parts of guar split that had been double purified were added. The reactor was sealed and purged three times with nitrogen. The pressure was reduced to -10 in-Hg, and propylene oxide 450
Parts were added at a temperature of 144 ° F (62 ° C). 162 ゜ F (72
° C) and the pressure was maintained at 10 psig by controlling the addition of propylene oxide. 56 additions of propylene oxide
Finished in minutes. Increase the temperature by 1 until the pressure drops to -5in-Hg.
Maintained at 59-162 ° F (71-72 ° C). The reactor was then purged twice with nitrogen and pressurized to 5 psig with nitrogen. 159 ゜ F
(71 ° C.) for 15 minutes, and then nitrogen purge and pressurization were repeated. The pressure was then reduced to -10 in-Hg and a solution of 176 parts of dimethylaminopropyl chloride hydrochloride dissolved in 740 parts of water was added. The temperature was maintained at 160 ° F (71 ° C) for 10 minutes. 350 parts of a 50% aqueous sodium hydroxide solution and 100 parts of water were added. Heating at 160 ° F was continued for 2 hours. The contents of the reactor were cooled to room temperature and washed three times with water. The resulting guar split derivative was then ground and dried with hot air at 550 ° F (288 ° C).

Example 5 From the guar derivative products of Examples 1, 2, 3 and 4 the guar derivative per 1000 gallons (3785) of this guar derivative in water containing 2% potassium chloride
By adding at a rate of 40 pounds (18.1 kg),
A thickened aqueous solution was prepared. After a hydration time of 2 hours, the pH was adjusted to 8.0 with dilute sodium hydroxide.
The viscosity was measured with a fan 35 type viscometer. A 3% aqueous solution of calcium hypochlorite was added at a ratio of 2.25 gallons to 1000 gallons. Thereafter, the viscosity was measured over time for 10 minutes.

 The results of the viscosity measurements are shown in the following table.

The principle, preferred embodiments, and functions of the present invention have been described above. However, the above disclosure is not intended to be limiting and is merely an example, so the present invention is not limited thereto. Various changes and modifications can be made by those skilled in the art within the scope of the present invention.

Claims (11)

(57) [Claims] 1. A dialkylaminoalkyl ether-hydroxyalkyl ether derivative of polygalactomannan. 2. The substitution degree (DS) of the tertiary aminoalkyl ether group is in the range of about 0.001 to 0.2, and the molecular substitution degree (MS) of the hydroxyalkyl group is in the range of about 0.05 to 1.6. Item 7. The compound according to Item 1. 3. The polygalactomannan is guar gum or locust bean gum, wherein the dialkylaminoalkyl ether has 1 to 6 carbon atoms in each alkyl group and 12 or less carbon atoms in the alkyl group, and The compound according to claim 1 or 2, wherein the alkyl group of the hydroxyalkyl ether group has 2 to 4 carbon atoms. 4. The dialkylaminoalkyl ether group is a dimethylaminoisopropyl ether group, and the hydroxyalkyl group is a hydroxypropyl group.
A compound according to claim 3. 5. A method for reducing the viscosity of an aqueous fluid thickened by a dialkylaminoalkyl ether-hydroxyalkyl ether derivative of polygalactomannan, wherein said aqueous fluid contains an alkali metal and an alkaline earth metal hypochlorite. Adding a hypochlorite or a chlorinated isocyanurate compound selected from salts. 6. The method of claim 5, wherein said polygalactomannan ether has a DS in the range of about 0.001 to 0.2 and an MS in the range of about 0.05 to 1.6. 7. The polygalactomannan is guar gum, the dialkylaminoalkyl ether has 1 to 6 carbon atoms in each alkyl group and a total of 12 or less carbon atoms, and 7. An alkyl group having 2 to 4 carbon atoms.
The described method. 8. The method according to claim 7, wherein said dialkylaminoalkyl ether group is a dimethylaminoisopropyl ether group and said hydroxyalkyl ether group is a hydroxypropyl ether group. 9. The method according to claim 5, wherein said hypochlorite is sodium or calcium hypochlorite, and said chlorinated isocyanurate is sodium dichloro-s-triazinetrione. The described method. 10. The method of claim 10 wherein said aqueous fluid is 1000 gallons of aqueous fluid (37
10. A process according to any one of claims 5 to 9 containing about 10 to 80 pounds (4.53 to 36.3 kg) of polygalactomannan dialkylaminoalkylether-hydroxyalkylether per 85). 11. The method of claim 5 wherein said hypochlorite or chlorinated isocyanurate is added in an amount of about 0.1 to 5 pounds per 1,000 gallons of aqueous fluid.
The method according to any one of claims 1 to 4.